Platelike workpieces are machined individually in many different ways, such as, for example, in drilling, punching and milling operations. The time required for the various steps besides the actual machining can be substantial; the steps include clamping and unclamping the workpieces on a support, moving into alignment with the tool, checking dimensions, etc. Consequently, the machining of individual small parts can involve substantial amounts of time and resultant substantial expense.
Accordingly, it has long been proposed to assemble a plurality of plate-like workpieces of the same size into a stack which could be simultaneously machined. Generally, the workpieces must be assembled in some form of a jig and then clamped together. However, this arrangement of the workpieces in a stack encounters limitations in that the clamping means will frequently interfere with the machining operations, such as, for example, when the machining operation is being performed by an end milling cutter, in which instance the clamping means might come into contact with the milling tool. As a result, it is necessary to move the clamping means a number of times during the machining operation so that the time advantage theoretically gained by assembling the plate-like pieces into a stack is substantially lost. Moreover, the clamping and unclamping operation can produce substantial problems in reorienting the several pieces of the stack in the exact alignment since otherwise inaccuracies in the multiple machining operation will occur.
It is an object of the present invention to provide a novel machine tool for the simultaneous machining of a stack of plate-like workpieces wherein the workpieces are firmly maintained in initial assembly throughout the machining operations.
It is also an object to provide such a machine tool in which the workpieces may be accurately positioned throughout the several operations without obstruction by clamping means and wherein the elements of the stack may be simultaneously or concurrently machined rapidly and accurately.
Another object is to provide such a machine tool in which movement of the stack of workpieces is effected between the several machining operations of the tool so as to permit facile and rapid performance of a multiplicity of operations upon the workpieces.